• Piboon Kirdphoksap B.Sc. (Industrial Technology)
• Pravej Serichetaphongse D.D.S., M.S. (Prosthodontics)
• Em-on Benjavongkulchai B.Sc. (Chemistry), M.Sc (Biochemistry), Ph.D. (Plant Biochemistry)
• Suphot Phattanasri B.Sc., M.E. (Chemical Eng.), D.Eng. (Hydrocarbon Chemistry)
• Pichaya Rachdawong B.E. (Environmental Eng.), M.Sc. (Civil Eng.), Ph.D. (Environmental Eng.)
• Wannadara Intarapanya B.Sc. (Chemistry)
• Jantarawan Tancharoen B.Sc. (Physics), M.B.A. (Finance)

Objective To investigate the quality of sewage water, the amounts of heavy metals, and the environmental
effects of the dental substances, chemicals, and hazardous substances within the Faculty of
Dentistry, Chulalongkorn University, which has not enough data. As a consequence, the study results
will be used as a considering factor in the system-designing project for sewage water treatment, along
with assigning the way of usage, storage and disposal of chemicals and hazardous substances.

Materials and methods This present study was conducted by random sampling the sewage water,
wastewater and fresh water at ten locations within the peak periods of the laboratorial studies and the
dental services as the samples of this study. The sewage water and wastewater from two locations were
treated before being discharged. Then, all samples were introduced to the analytical processes to
determine the quality of sewage water/wastewater and the amounts of three heavy metals according to
the standard methods.

Results The mean amounts of mercury in the wastewater from Building 5, Building 10 and Building
15 were over the criteria, together with the mean amounts of Biological Oxygen Demand; Fat, Oil and
Grease; and suspended solids in the wastewater from Building 10 were higher than the criteria. However,
the analytical results of fresh water of each building were in the criteria.

Conclusion Due to the usage of fresh water in teaching in the laboratory, researches, dental services,
and consumption; the sewage water within this Faculty really contained mercury, Biological Oxygen
Demand; Fat, Oil and Grease; and suspended solids. On comparison of the data between sewage water
and wastewater, it could be concluded that the mean amounts of water quality were improved after
being treated, while the mean values of heavy metals had no significant differences since the wastewater
treatment system was not designed for treating the heavy metals.

(CU Dent J. 2008;31:283-94)